Environmental embrittlement of Ti-48Al alloys

The tensile behaviour of two TiAl48 alloys, namely Ti47Al48Cr2Nb2B1 and Ti5 2Al48, was studied with respect to the gaseous environment. The samples wer e annealed to give them a duplex microstructure, consisting of equiaxed gam ma-TiAl grains and lamellar gamma/alpha(2) grains. They were tensile tested at room temperature in pure argon gas or in water vapour saturated argon g as. Elongation was found rather low in the dry gas. It was reduced still fu rther in moisture with respect to dry argon even in the case of Ti47Al48Cr2 B1 where additions, such as Cr, were thought to lessen the environmental em brittlement.